▪ Thyroid storm, also known as thyrotoxic crisis, is an acute, life-
threatening complication of hyperthyroidism.
▪ It is an exaggerated presentation of thyrotoxicosis.
▪ It comes with sudden multisystem involvement.
▪ The mortality associated with thyroid storm is estimated to be 8 to
25% despite modern advancements in its treatment and supportive
measures. Thus, it is very important to recognize it early and start
aggressive treatment to reduce mortality.
▪ The diagnosis of thyroid storm is clinical.
▪Superimposed precipitating factors cause thyroid storm
in patients with diagnosed or undiagnosed
▪It is more common with Graves disease but can occur
with other aetiologies of hyperthyroidism, such as toxic
multinodular goitre and toxic thyroid adenoma
4. The precipitating factors are:
• Abrupt discontinuation of antithyroid medicine
• Thyroid surgery
• Non-thyroid surgery
• Acute illnesses like infections including Covid-19, diabetic
ketoacidosis, acute myocardial infarction, cardiovascular
accident, cardiac failure, and drug reactions.
5. • Parturition
• Recent use of Iodinated contrast medium
• Radioiodine therapy (rare)
• Stroke or traumatic brain injury
• Medication side effects, e.g., amiodarone, anaesthetics,
• Hyperemesis gravidarum in pregnancy
▪ It is a rare presentation of hyperthyroidism.
▪ Thyroid storm accounts for about 1% to 2% of admissions for
▪ As per the United States survey, the incidence of storm ranged from
0.57 to 0.76 cases per 100,000 per year in the normal population and
4.8 to 5.6 cases per 100,000 per year in hospitalized patients.
▪ As per the Japanese National Survey, the incidence of thyroid storm
was 0.2 per 100,000 population per year, about 0.22% of all
thyrotoxicosis patients and 5.4% of hospitalized thyrotoxicosis
7. ▪ The average age of people with thyroid storm was 42 to
43 years, similar to those with thyrotoxicosis without
▪ The male to female ratio for the incidence of thyroid
storm was about 1:3, similar to thyrotoxicosis without
▪ The pathophysiological basis for precipitation of thyroid storm in
patients with thyrotoxicosis is unclear.
▪ But, as mentioned above, a precipitating factor is always required
to cause thyroid storm. Several hypotheses have been proposed.
▪ One theory suggests the incidence of thyroid storm is due to the
rapid increase in thyroid hormone levels rather than the absolute
hormone level that occurs during thyroid surgery, following
radioactive iodine treatment, after sudden discontinuation of the
antithyroid drug, or after administration of the large dose of iodine
in contrast studies.
9. ▪ The hyperactivity of the sympathetic nervous system with increased
response to catecholamine along with an increased cellular response
to thyroid hormone during acute stress or infections, causing
cytokines release and altered immunological disturbances, are other
possible mechanisms of thyroid storm.
▪ The clinical features are due to the exaggerated effects of the thyroid
hormone. There is an intense metabolic activity that increases
▪ The resulting tachycardia to meet the oxygen requirements can
induce heart failure and predisposes the patient to arrhythmias.
Similarly, CNS symptoms include irritability, seizures, delirium, and
▪ Histopathology depends on the cause of the thyroid storm.
▪ The most common cause of Graves disease is diffuse follicular
hyperplasia, along with increased thyroid receptor antibodies
and increased vascularization of the tissue.
▪ If it is a tumor-originated storm, malignant cells infiltrate and
destroy the thyroid tissue and rupture the follicles.
12. History and Physical
▪ Presentation of thyroid storm is an exaggerated manifestation of
hyperthyroidism, with the presence of an acute precipitating
▪ Fever, cardiovascular involvement (including tachycardia, heart
failure, arrhythmia), central nervous system
(CNS) manifestations, and gastrointestinal symptoms are
▪ Fever of 104 F to 106 F with diaphoresis is a key presenting
13. ▪ Cardiovascular manifestations include tachycardia of more than
140 HR/minute, heart failure with pulmonary and peripheral
oedema, hypotension, arrhythmia, and death from cardiac arrest.
▪ CNS involvement includes agitation, delirium, anxiety,
psychosis, or coma.
▪ Gastrointestinal (GI) symptoms include nausea, vomiting,
diarrhoea, abdominal pain, intestinal obstruction, and acute
▪ Physical examination findings may include high temperature,
tachycardia, orbitopathy, goitre, hand tremors, moist and warm
skin, hyperreflexia, systolic hypertension, and jaundice.
▪ The diagnosis of thyroid storm needs clinical suspicion based on
the presentation mentioned above in a patient with
hyperthyroidism or suspected hyperthyroidism.
▪ Thyroid function tests can be obtained, which usually show high
FT4/FT3 and low TSH.
▪ Other lab abnormalities may include hypercalcemia,
hyperglycemia (due to inhibition of insulin release and increased
glycogenolysis), abnormal LFTs, and high or low white blood cell
15. Burch-Wartofsky Point Scale (BWPS)
In 1993, the following scoring system for the diagnosis of thyroid
storm was introduced:
• Temperature: 5 points per 1 F above 99 F (maximum 30 points)
• CNS dysfunction: 10 points for mild (agitation), 20 for moderate
(delirium, psychosis, or extreme lethargy), and 30 for severe
(seizure or coma)
• Tachycardia: 5 (99-109), 10 (110 -119), 15 (120 -129), 20 (130 -
139) and 25 (greater than 140)
16. • Presence of atrial fibrillation:10
• Heart failure: 5 for mild (pedal oedema), 10 for moderate (bi-
basilar rales), 15 for severe (pulmonary oedema)
• GI dysfunction: 10 for moderate (diarrhoea, nausea/vomiting, or
abdominal pain) and 20 for severe (unexplained jaundice)
• Presence of Precipitating factor: 10 points
Diagnosis: A total score of more than 45 is highly suggestive of
thyroid storm, 25 to 44 supports the diagnosis, and less than 25
makes the diagnosis unlikely.
17. The Japanese Thyroid Association (JTA)
▪ This is a different scoring system based on similar clinical findings.Thyrotoxicosis
(elevated FT3 and/or FT4) is a prerequisite, and it requires various combinations of
the following symptoms:
• CNS manifestation (restlessness, delirium, psychosis/mental aberration,
• Fever (38 C/100.4 F or greater)
• Tachycardia (130/min or higher)
• CHF (pulmonary edema, rales, cardiogenic shock, or NYHA class IV)
• GI/Hepatic Manifestation (Nausea, vomiting, diarrhea, total Bilirubin 3 mg/dl or
▪ Definite Thyroid Storm (TS1): Thyrotoxicosis (elevated FT3 and/or FT4) plus
At least one CNS manifestation plus one or more other symptoms (fever,
tachycardia, CHF, GI/Hepatic) ‘OR’ A combination of at least three features
among fever, GI/Hepatic, CHF, or tachycardia
▪ Suspected Thyroid Storm (TS2): Thyrotoxicosis (elevated FT3 and/or FT4)
A combination of at least two features among tachycardia, CHF, GI/Hepatic,
Fever ‘OR’ A patient with h/o thyroid disease, presence of goiter and
exophthalmos who meets criteria for TS1 but TFTs not available
19. Treatment / Management
▪ Treatment of thyroid storm consists of supportive measures like
intravenous (IV) fluids, oxygen, cooling blankets, and
acetaminophen, as well as specific measures to treat
▪ If any precipitating factors, for example, infection, are present,
that needs to be addressed. Patients with thyroid storm must be
admitted to the intensive care unit with close cardiac monitoring
and ventilatory support if needed.
20. ▪ Specific Strategic Steps for Treatment
1.Therapy to control increased adrenergic tone: Beta-blocker
2.Therapy to reduce thyroid hormone synthesis: Thionamide
3.Therapy to reduce the release of thyroid hormone: Iodine
4.Therapy to block peripheral conversion of T4 to T3: Iodinated
radiocontrast agent, glucocorticoid, PTU, propranolol
5.Therapy to reduce enterohepatic recycling of thyroid hormone:
Bile acid sequestrant
22. Differential Diagnosis
Thyroid storm should be differentiated from other diseases with similar symptoms
and signs. Fever is the most common presentation of multiple conditions; therefore,
it can be misdiagnosed. The differential diagnoses include:
• Cocaine use
• Neuroleptic malignant syndrome
23. Surgical Oncology
▪ If toxic adenoma or multinodular goiter is causing this disease, then
surgical resection and radioactive iodine ablation are the mainstays of
▪ Thyroidectomy is preferred if a patient has compressive symptoms.
▪ Patients who refuse ablation or have contraindications to surgery can be
treated with long-term antithyroid medicine
▪ Grave's disease with intrathoracic mass causes severe compressive
symptoms, and thyroidectomy is preferred in these cases.
▪ Thyroidectomy has other adverse effects, like recurrent laryngeal nerve
damage and hypoparathyroidism.
24. Radiation Oncology
Radioiodine-131 (I) therapy is helpful in hyperfunctioning
nodules, but the risk of hypothyroidism is 60% after a 20-year
follow-up in a retrospective study.
Other factors increasing the risk of hypothyroidism in these
• Methimazole therapy